Soap



Patented Feb. 9, 1943 soar Richard Thomas and Henry Bowen Oakley, Bromborough, England, assignors to Lever Brothers Company, a corporation of Maine No Drawing. Application November 22, 1939, Se-

rial No. 305,728. In Great Britain November 22,

Claims;

This invention relates to improvements in soap and soap products and has for its main object to provide soap and soap products having improved hard water characteristics.

In our co-pending applications Serial Nos. 197,376, 197,377 and 197,378 filed March 22, 1938,

which have now issued as Patents Numbers I 2,277,728, 2,277,729 and 2,277,730, respectively, on March 31, 1942, we have described methods for the production of soap and soap products which can be dissolved in hard water with little or no precipitation of insoluble soaps or formation of scum, the solution when boiled remaining clear or substantially clear. According to the said applications, such products can be obtained by incorporating phosphates in certain quantities with soaps derived from fatty acids comprising relatively large proportions of polyethylenic and monoethylenic fatty acids and relatively small proportions of saturated fatty acids, the products being produced in a form which will ensure rapid solution in water. It has been shown in the said specifications that saturated fatty acids having from 12 to 18 carbon atoms in the molecule tend to have an adverse effect upon the soap products, this effect being the greater the higher the molecular weight, so that if the saturated acids consist substantially of palmitic or stearic acid or both these acids, the proportion in the fatty acid mixture must not exceed about 20 per cent.

We have now made the surprising discovery that while the detrimental effect of the saturated fatty acids having from 12 to 18 carbon atoms in the molecule increases with the molecular weight, this does not hold good in the case of saturated fatty acids having more than 18 carbon atoms in the molecule, such as, for example,

arachidic (20 carbon atoms), behenic r 22 carbon atoms) and lignoceric (24 carbon atoms) acids. It has been found that not only may these fatty acids be present in larger quantities than palmitic and stearic acid, but that their presence within certain limits actually enhances the clarity of the soap solution and even-allows of the incorporation of larger quantities of saturated fatty acidshaving 18 C atoms or less in the molecule. It hfifsflfurther been found that Whereas the soap-{products described in the above-mentioned specifications contain certain quantities of phosphates, the addition of phosphates is not necessarily required in the case of soaps derived from fatty acids which comprise acids containing at least 20 C atoms in the molecule as more particularly described below.

The invention consists in a process for the manufacture of soaps or soap products in a form which will ensure rapid solution in water, in which the soaps are derived from fatty acids containing from 10 to 30 per cent. of saturated acids having more than 18 C atoms in the molecule, at least 30 per cent. of unsaturated acids, and not more than 30 per cent. of palmitic acid or of a mixture of palmitic and stearic acids whereof the stearic. acid does not exceed about 15 per cent. of the total fatty acids in the soap, any other saturated acids present being of lower molecular weight than palmitic acid. 7

In order to ensure rapid solution in water, the soaps and soap products must be in a finely divided form such as powder flakes, threads, parings, puffed granules, pellets or the like.

Although, as pointed out above, the addition of phosphates is not necessarily required, we prefer to incorporate phosphates, as these considerably improve the properties of the product, particularly when used for washing at the boiling temperature. 1

The phosphates which can be used are the orthophosphates, pyrophosphates, polyphosphates and metaphosphates of sodium and. mixtures thereof. Of the orthohosphates, however, monosodium dihydrogen phosphate owing to its acid reaction is incompatible with soaps unless used in very small quantities, but can be employed in conjunction with caustic soda or other suitable alkaline reacting substance, in which case, of course, its use is equivalent to the use of the disodium or trisodium phosphate.

The proportions of phosphates preferably to be incorporated are largely dependent upon the composition of the soap and may also vary according to the nature of the product desired. It has been found that as a general rule the following ratios of phosphate (calculated as anhydrous salt) to fatty acid have given very satisfactory results:

Orthophosphate to fatty acid, from 1:10 to 1:4 Pyrophosphate to fatty acid, from 1:10 'to 1:4 Polyphosphate to fatty acid, from 1:4 to 1:2 Met-aphosphate to fatty acid, from 1:4 to 1:2

saturated fatty acids having more than 18 C atoms in the molecule depends to some extent on their molecular weight, the .acids having 22 to 24 C atoms being somewhat more efficient than acids having 20 C atoms; (2) the adverse effect of saturated acids having from 12 to 18 C atoms in the molecule increases considerably with the molecular weight, being only slight in the case of lauric acid, but very pronounced in the case of stearic acid. The higher the molecular weight of the saturated fatty acids present the lower should be the proportion in the mixture.

A small proportion of rosin can be included in the fatty acid mixtures.

Examples 1) Fifty parts of groundnut oil, 25 parts of palm oil, parts of rosin and 20 parts of the higher fraction obtained in the distillation of fatty acids made from hardened herring oil, which fraction consists substantially of behenic acid (two thirds) and lignoceric acid (one third), is converted into soap, and to 80 parts of the soap in the molten condition are added 15 parts of hydrated disodium monohydrogen phosphate and 5 parts of hydrated trisodium phosphate. The mixture is spray-dried in the known mannor to produce a free-flowing powder.

(2) sixty parts of groundnut oil, parts of palm oil, 25 parts of fully hardened herring oil and 5 parts of rosin are converted into soap and to 90 parts of the molten soap, containing-about 60 per cent. fatty acids, are added 8.5 parts of anhydrous disodium monohydrogen phosphate and 1.9 parts of 100 TW. caustic soda. The mixture is spray-dried in the known manner to produce a free-flowing powder."

(3) Fifty parts of groundnut oil, 25 parts of palm oil, 20 parts of distilled fatty acids from hardened herring oil containing 23 per cent. Cm and 77 per cent. C20 (and little or no C22 and C24) saturated fatty acids, and 5 parts of rosin are converted into soap. To 91 parts of the molten soap containing 63 per cent. fatty acids are added 4.5 parts of anhydrous disodium monohydrogen phosphate and 4.5 parts of anhydrous trisodium phosphate, and the mixture is blown into air in the known manner to produce a freeilowing powder.

(4) Fifty parts of groundnut oil, 35 parts of palm oil, 5 parts of rosin and 10 parts of the higher fraction of hardened herring oil distillate mentioned in Example 1 are saponified and the liquid soap converted into soap flakes in the known manner. v

5) Eighty parts of liquid soap of the composition mentioned in Example 4 are mixed with 12 parts of hydrated disodium phosphate and 8 parts of hydrated trisodium phosphate and the mixture is blown into air in the known manner to produce a free-flowing powder.

(6) Fifty parts of groundnut oil, 25 parts of coconut oil, 5 parts of distilled fatty acids from hardened herring oil containing about 66 per cent. C22 and 34 per cent. C24 saturated fatty acids, parts fully hardened herring oil and 5 parts of rosin are '-converted into soap. To 90 parts of the molten soap containing 63 per cent. fatty acids are added 10 parts of anhydrous sodium pyrophosphate and the mixture sprayed into heated air in the known manner to produce a free-flowing soap powder.

('7) To 76 parts of soap of the composition mentioned in Example 1, containing 63 per cent. fatty acids, are added 24 parts of anhydrous sodium polyphosphate and the mixture blown into air in the known manner to produce a free-flowing powder.

We claim:

1. A soap product having improved hard water characteristics comprising a water-soluble soap of a mixture of soap forming fatty acids, said soap forming fatty acids comprising about 10 to of saturated acids having more than 18 carbon atoms, at least about 30% of unsaturated acids, not more than 30% of a mixture or palmitic and stearic acids whereof the stearic acid does not exceed 15% of the total fatty acids, and any other saturated acids present being of lower molecular weight than palmitic acid, said soap product being in a solid finely divided form to insure rapid solution in water, whereby said soap product may be dissolved in hard water without substantial precipitation of insoluble soaps;

2. A soap product having improved hard water characteristics comprising a water soluble soap-of a mixture of soap forming fatty acids, said soap forming fatty acids comprising about 10 to 30% of saturated acids having more than 18 carbon atoms, at least about 30% of unsaturated acids, not more than 30% of a mixture of palmitic and stearic acids whereof thestearic acid does not exceed 15% of the total fatty acids, and any other saturated acids present being of lower molecular weight than palmitic acid: and an by Weight 1 part of an alkali-metal phosphate selected from the group consisting of alkaline-reacting orthophosphates, pyrophosphates, polyphosphates and metaphosphates, the amount of said orthophosphates and pyrophosphates calculated as an anhydrous salt being 1 part to 4 to 10 parts by weight of the fatty acids in said soap, the amount of said polyphosphate and metaphosphates calculated as an anhydrous salt being 1 part by weight to 2 to 4 parts of the fatty acids in said soap, said soap product being in a solid finely divided form to insure rapid solution in water, whereby'said soap product may be dissolved in hard water without substantial precipitation of insoluble soaps.

3. A soap product having improved hard water characteristics comprising a water soluble soap of a mixture of soap forming fatty acids, said soap forming fatty acids comprising about 10 to 30% of saturated acids having more than 18 carbon atoms, at least about 30% of unsaturated acids, not more than 30% of a.

mixture of palmitic and stearic acids whereof the stearic acid does not exceed 15% of the total fatty acids, and any other saturated acids present being of lower molecular weight than palmitic acid, and by weight 1 part of an alkaline-reacting alkali-metal orthophosphate calculated as an anhydrous salt to 4 to 10 parts of the fatty acids in said soap, said soap product being in a solid finely divided form to insure rapid solution in Water, whereby said soap product may be dissolved in hard water without substantial precipitation of insoluble soaps.

4. A soap product having improved hard water characteristics comprising a water soluble soap of a mixture of soap forming fatty acids, said soap forming fatty acids comprising about 10 to 30% of saturated acids having more than 18 carbon atoms, at least about 30% of unsaturated acids, not more than 30% of a mixture of palmitic and stearic acids whereof the stearic acid does not exceed 15% of the total fatty acids acids present being of lower molecular weight than palmitic acid, and

phate calculated as an anhydrous salt to 4 to 10 alkali-metal pyrophosparts of the fatty acids in said soap, said soap product being in a solid finely divided form to insure rapid solution in water, whereby said soap product may be dissolved in hard water without stearic acid does not exceed 15% of the total fatty acids and any other saturated acids present being of lower molecular weight than palmitic acid, and by weight 1 part of an alkali-metal polyphosphate calculated as an anhydrous salt to 2 to 4 parts of the fatty acids in said soap, said soap product being in a solid finely divided form to insure rapid solution in water, whereby said soap product may be dissolved in hard water without substantial precipitation of insoluble soaps.

RICHARD THOMAS. HENRY BOWEN OAKLEY. 

